Summary for West Indian Ocean and Southern Africa

Synopsis: ENSO-neutral conditions have returned and are favored to continue through at least the Southern Hemisphere fall 2017.

La Niña conditions are no longer present, with slightly below-average sea surface temperatures (SSTs) observed across the central equatorial Pacific and above-average SSTs increasing in the eastern Pacific. The latest weekly Niño index values were -0.3°C in the westernmost Niño-4 and Niño-3.4 regions, and +1.5°C in the easternmost Niño-1+2 region. The upper-ocean heat content anomaly increased during January and was slightly positive when averaged across the eastern Pacific, a reflection of above-average temperatures at depth. Atmospheric convection remained suppressed over the central tropical Pacific and enhanced over Indonesia. The low-level easterly winds were slightly enhanced over the western tropical Pacific, and upper-level westerly winds were near average. Overall, the ocean and atmosphere system is consistent with ENSO-neutral conditions.

Most models predict the continuation of ENSO-neutral (3-month average Niño-3.4 index between -0.5°C and 0.5°C) through the Southern Hemisphere winter. However, a few dynamical model forecasts, including the NCEP CFSv2, anticipate an onset of El Niño as soon as the Southern Hemisphere fall (March-May 2017). Because of typically high uncertainty in forecasts made at this time of the year for the upcoming fall and winter, and the lingering La Niña-like tropical convection patterns, the forecaster consensus favors ENSO-neutral during the fall with a ~60% chance. Thereafter, there are increasing odds for El Niño toward the second half of 2017 (~50% chance in September-November). In summary, ENSO-neutral conditions have returned and are favored to continue through at least the Southern Hemisphere fall 2017.

February Temperature

Tanzania through DR Congo across to the Republic of Congo should be slightly to moderately cooler than normal along with much of Namibia, Botswana, and Zimbabwe. The rest of Southern Africa should be moderately to extremely warmer than normal. The Seychelles and Mauritius should be warmer than normal and Madagascar also warmer than normal.

February Precipitation

Eastern South Africa should be slightly drier than normal with Mozambique, Zimbabwe and Botswana and the Congo being slightly wetter than normal along with Madagascar. Tanzania and to the west coast to Luanda should be slightly drier than normal.